#!/bin/bash

# Wrapper script for find-debuginfo.sh

#

# Usage:

#  wrap-find-debuginfo.sh SYSROOT-PATH SCRIPT-PATH SCRIPT-ARGS...

#

# The wrapper saves the original version of ld.so found in SYSROOT-PATH,

# invokes SCRIPT-PATH with SCRIPT-ARGS, and then restores the

# LDSO-PATH file, followed by note merging and DWZ compression.

# As a result, ld.so has (mostly) unchanged debuginfo even

# after debuginfo extraction.

#

# For libc.so.6, a set of strategic symbols is preserved in .symtab

# that are frequently used in valgrind suppressions and elsewhere.

set -ex

workdir="$(mktemp -d -t find_debuginfo.XXXXXX)"

ldso_tmp="$workdir/ld.so"

libc_tmp="$workdir/libc.so"

# Prefer a separately installed debugedit over the RPM-integrated one.

if command -v debugedit >/dev/null ; then

    debugedit=debugedit

else

    debugedit=/usr/lib/rpm/debugedit

fi

cleanup () {

    rm -rf "$workdir"

}

trap cleanup 0

sysroot_path="$1"

shift

script_path="$1"

shift

# See ldso_path setting in glibc.spec.

ldso_path=

for ldso_candidate in `find "$sysroot_path" -maxdepth 2 \

  -regextype posix-extended -regex '.*/ld(-.*|64|)\.so\.[0-9]+$' -type f` ; do

    if test -z "$ldso_path" ; then

	ldso_path="$ldso_candidate"

    elif [ -f "$sysroot_path/lib64/ld-linux-x86-64.so.2" ] && [ -f "$sysroot_path/lib/ld-linux.so.2" ]; then

	# x86_64 with 32-bit libc built for glibc32 as well.  Finding

	# multiple dynamic linkers is expected, not a bug; ensure the

	# 64-bit one is used.

	ldso_path="$sysroot_path/lib64/ld-linux-x86-64.so.2"

    else

	echo "error: multiple ld.so candidates: $ldso_path, $ldso_candidate"

	exit 1

    fi

done

# libc.so.6 always uses this name, so it is simpler to locate.

libc_path=

for libc_candidate in `find "$sysroot_path" -maxdepth 2 -name libc.so.6`; do

    if test -z "$libc_path" ; then

	libc_path="$libc_candidate"

    elif [ -f "$sysroot_path/lib64/ld-linux-x86-64.so.2" ] && [ -f "$sysroot_path/lib/ld-linux.so.2" ]; then

	# x86_64 with 32-bit libc built for glibc32 as well.  The test

	# here uses ld.so paths, not libc paths, to ensure it doesn't

	# apply on any other architecture.

	libc_path="$sysroot_path/lib64/libc.so.6"

    else

	echo "error: multiple libc.so.6 candidates: $libc_path, $libc_candidate"

	exit 1

    fi

done

# Preserve the original files.

cp "$ldso_path" "$ldso_tmp"

cp "$libc_path" "$libc_tmp"

# Run the debuginfo extraction.

"$script_path" "$@"

# libc.so.6: Extract the .gnu_debuglink section

objcopy -j.gnu_debuglink --set-section-flags .gnu_debuglink=alloc \

  -O binary "$libc_path" "$libc_tmp.debuglink"

# Restore the original files.

cp "$ldso_tmp" "$ldso_path"

cp "$libc_tmp" "$libc_path"

# Reduce the size of notes.  Primarily for annobin.

objcopy --merge-notes "$ldso_path"

objcopy --merge-notes "$libc_path"

# libc.so.6: Restore the .gnu_debuglink section

objcopy --add-section .gnu_debuglink="$libc_tmp.debuglink" "$libc_path"

# ld.so does not have separated debuginfo and so the debuginfo file

# generated by find-debuginfo is redundant.  Therefore, remove it.

ldso_debug=

for ldso_debug_candidate in `find "$sysroot_path" -maxdepth 2 \

    -regextype posix-extended \

  -regex '.*/ld(-.*|64|)\.so\.[0-9]+.*debug$' -type f` ; do

    if test -z "$ldso_debug" ; then

	ldso_debug="$ldso_debug_candidate"

    else

	echo "error: multiple ld.so debug candidates: $ldso_debug, $ldso_debug_candidate"

	exit 1

    fi

done

rm -f "$ldso_debug"

# libc.so.6: Reduce to valuable symbols.  Eliminate file symbols,

# annobin symbols, and symbols used by the glibc build to implement

# hidden aliases (__EI_*).  We would also like to remove __GI_*

# symbols, but even listing them explicitly (as in -K __GI_strlen)

# still causes strip to remove them, so there is no filtering of

# __GI_* here.  (Debuginfo is gone after this, so no need to optimize

# it.)

strip -w \

    -K '*' \

    -K '!*.c' \

    -K '!*.os' \

    -K '!.annobin_*' \

    -K '!__EI_*' \

    -K '!__PRETTY_FUNCTION__*' \

    "$libc_path"

# ld.so: Rewrite the source file paths to match the extracted

# locations.  First compute the arguments for invoking debugedit.

# See find-debuginfo.sh.

debug_dest_name="/usr/src/debug"

last_arg=

while true ; do

    arg="$1"

    shift || break

    case "$arg" in

	(--unique-debug-src-base)

	    debug_dest_name="/usr/src/debug/$1"

	    shift

	    ;;

	(-*)

	    ;;

	(*)

	    last_arg="$arg"

	    ;;

    esac

done

debug_base_name=${last_arg:-$RPM_BUILD_ROOT}

$debugedit -b "$debug_base_name" -d "$debug_dest_name" -n $ldso_path

# Remove the .annobin* symbols (and only them).

if nm --format=just-symbols "$ldso_path" \

	| grep '^\.annobin' > "$ldso_tmp.annobin-symbols"; then

    objcopy --strip-symbols="$ldso_tmp.annobin-symbols" "$ldso_path"

fi

# Apply single-file DWARF optimization.

dwz $ldso_path